I. Field of the Invention
The present invention relates to a positive sealing inlet (PSI) valve assembly for the fill tube on the fuel tank of an automotive vehicle.
II. Description of the Prior Art
In previously known automotive vehicles, a fill tube is provided between the exterior of the automotive vehicle and the fuel tank. While in many previously known automotive vehicles, the fill tube is merely covered by a removable fill cap, in other types of previously known automotive vehicles, a PSI valve is provided across the fill tube. This PSI valve is designed to minimize the escape of fuel vapors from the fuel tank through the fill tube.
These previously known PSI valves, however, have been rather rudimentary in design. As such, these previously known PSI valves reduce, but do not eliminate, the escape of fuel vapors from the fuel tank through the fill tube. However, in view of ever increasing governmental regulations regarding the emissions of fuel vapors into the atmosphere, these previously known PSI valves have proven inadequate to meet government standards.
One reason that these previously known PSI valves have been unable to meet government standards is that the PSI valve is secured to the fill tube by fasteners extending through the fill tube. These fasteners, however, create openings in the fill tube which can permit the escape of fuel vapors through these fastener openings, particularly after extended use of the automotive vehicle.
A still further disadvantage of these previously known PSI valves is that the attachment of the PSI valve to the fill tube was labor intensive and oftentimes required special tools. As such, these additional labor costs increased the overall cost of the PSI valve assembly.
The present invention provides a PSI valve assembly for the fill tube of an automotive vehicle which overcomes all of the above-mentioned disadvantages of the previously known devices.
In brief, the PSI valve assembly of the present invention comprises a tubular and cylindrical housing having both an interior and exterior surface. A wall is disposed across the interior of the housing adjacent one end of the housing and this wall includes a through opening. Preferably, the housing and the wall are of a one-piece plastic construction.
A flapper valve is pivotally secured to a valve holder so that the flapper valve is movable between an open and a closed position. In its closed position, the flapper valve overlies and fluidly seals the through opening in the housing wall. Conversely, with the flapper valve in its open position, the flapper valve is spaced away from the wall through opening thus permitting fuel to flow through the housing and to the fuel tank.
Unlike the previously known devices, however, the flapper valve as well as the valve holder is positioned within the interior of the housing. A fluid seal is disposed around the exterior surface of the housing and this fluid seal sealingly engages the interior of the fill tube. Furthermore, the exterior surface of the housing is continuous, i.e. has no openings, between the fluid seal and the housing end at which the flapper valve is mounted.
Since the entire exterior of the housing is continuous between the fluid seal between the housing and the fill tube and the end of the housing at which the flapper valve is mounted, the escape of fuel vapors from the fuel tank around the exterior of the housing is substantially precluded. Furthermore, in order to enhance the fluid seal between the flapper valve and the housing wall, a fluid seal is preferably disposed around the outer periphery of the PSI valve and this fluid seal engages the housing wall when the flapper valve is rotated to its assembled position.